Tuberculosis (TB) represents a major global infectious disease and a severe comorbidity in individuals with autoimmune disorders. Anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV) is a life-threatening autoimmune small-vessel vasculitis that requires long-term glucocorticoid and immunosuppressive therapy. Both the underlying immune dysregulation and intensive immunosuppression place AAV patients at remarkably high risk of TB infection. While prior studies have demonstrated an increased incidence of TB in AAV cohorts, few investigations have systematically evaluated the effect of concomitant TB on long-term clinical outcomes, especially all-cause mortality and progression to end-stage kidney disease (ESKD). The prognostic significance of coexisting TB in AAV patients remains insufficiently clarified, limiting optimal clinical decision-making. This study was designed to characterize the clinical features of AAV patients with TB and to determine the impact of TB on mortality and ESKD progression.

We conducted a retrospective cohort study enrolling 163 patients newly diagnosed with AAV between December 2013 and December 2023 from two tertiary medical centers. Baseline characteristics, laboratory data, treatment regimens, and follow-up outcomes were collected from electronic medical records. Propensity score matching (PSM) was performed to balance confounding factors including demographics, comorbidities, AAV subtypes, and therapeutic strategies. The primary endpoints were all-cause mortality and progression to ESKD during the follow-up period.

Patients with concomitant AAV and TB had a significantly shorter time from symptom onset to diagnosis (P=0.012), higher mortality (P=0.025), and lower long-term survival (P=0.026) than matched controls. Deceased AAV patients exhibited higher white blood cell (P=0.035) and neutrophil counts (P=0.014) compared to survivors. Although TB was not a significant risk factor for ESKD progression (P=0.359), patients who progressed to ESKD had higher neutrophil (P=0.019) and lymphocyte counts (P=0.043).

TB is a significant risk factor for mortality in AAV patients. Elevated leukocyte and neutrophil counts are associated with mortality, while increased neutrophil and lymphocyte counts are linked to ESKD progression in AAV.